Coastal mangrove forests are known as one of the most productive ecosystems and efficient carbon (C) sinks on the planet. Mangroves store a substantial amount of organic C in below-ground sediment, which is known as “blue carbon (C)”. As anthropogenic factors have caused greenhouse gas (GHG) emissions and sea levels to increase, mangrove blue C has become a part of global climate change negotiations due to its potential for storing C and mitigating GHG emissions. However, these coastal forests are also currently under threat from major land-use and land-cover changes (LULCC) for aquaculture and agriculture, resulting in large amounts of deforested and degraded mangrove areas globally. Little is known about the range of impacts different LULCC have upon mangrove C dynamics (e.g. C storage, emission and sequestration). This systematic review protocol outlines the methodology to identify and quantify the impacts of LULCC upon the C dynamics of global mangrove forests. The forthcoming review will assess the magnitude of LULCC on natural and impacted mangroves and identify where research gaps remain on mangrove C dynamics